The invention concerns a process for the manufacture of a flexible press shell that is liquid-tight and smoothed on its inside, as well as a device for the application of this process.
A liquid-tight press shell smoothed on its inside serves preferably as a press element in a dewatering press, for instance on a papermaking machine. In doing so, the press shell is forced, with the aid of a press shoe arranged in the press shell, onto part of the circumference of a press roll. The press shell normally consists of a laminated body with a reinforcement fabric embedded in it. Sliding across the press shoe, the inside of the press shell must have a surface that is smooth and impermeable to liquid.
From the German patent document 32 31 039 A1 it is known to form the aforementioned smooth surface first on the outside of a continuous belt and thereafter turn the belt inside out, so that in using the belt the smoothed surface will be located on the inside of the belt.
The aforementioned turning is difficult in the manufacture of such a belt because it involves the risk that the continuous belt may be damaged. This applies especially when the circumference of the belt is relatively small as compared to its width, that is, the space between the two edges. It is quite possible that the circumference of the belt amounts to only one-half of its width. These cases are thus concerned with a tubular belt, which hereafter will be called, as it has already been called above, a "press shell."
The problem underlying the invention is to so advance a manufacturing process for the manufacture of a flexible press shell wherein the shell is liquid-tight and smoothed on its inside, and wherein the smoothing of the press shell takes place on the outside (turned inside out) so that the smoothed side will be the inside, that the turning of the press shell can be performed in a simple manner and without a risk of damage to the press shell. In addition, the problem underlying the invention also comprises proposing a device for the application of this process.